Although changes in patterns of fertility and marital and living arrangements in the United States have been well documented, not much is known regarding the consequences of these trends for those involved, especially children. Studies of the effects of family structure on child development have mostly been based on small, non-representative samples. Nevertheless, research results suggest that the economic, social, and psychological well-being of children are significantly related to family type. The goal of the proposed research is to explore the impact of family structure, parent marital history, and household composition on children's social development and emotional well-being; intellectual development; and physical health. Dependent variables in these areas will be explored as a function of family composition -- specifically, the number and type of parents residing in the household, the number and type of siblings, and the presence of extended family members. The analysis will be based on data about 16,000 children collected in 1981 as part of the Child Health Supplement of the Health Interview Survey. Two sets of analyses will be conducted. An initial set of regressions will be based on the total sample partitioned by the child's age, sex, and race. Measures of family composition will be included with social and economic control variables. A second set of regressions will be conducted on sub-samples partitioned by family type: 1) mother and father; 2) mother-only; 3) mother-stepfather; 4) father-only and father-stepmother families; and 5) children living with neither parent. Although less disaggregation by race, sex, and age will be possible in this set of regressions, an additional set of variables will be added to capture the often complex marital and family histories of these different family forms. These variables include the mother's marital history, the age of the child at first disruption, recently of the most recent transition, and frequency of contact with the absent parent.